Pros:
very fast paced, speed similar to Super Meat Boy
levels are fairly well designed, return routes bypass enemies
some difficult jumps/puzzles
sound is veryy good, good ambient music and water effects
background creates sense of place, outdoors when above ground
controls are at least simple, a button for ability and arrow keys to move,
can be changed

Cons:
graphics are blurred? Low res textures, noise?
Sometimes unclear where to go, walk through black houses/platforms that would otherwise be solid
no controller or mouse support (would be hugely beneficial)
generally poor graphic design on dialogue boxes, people (similar to virtual villagers)
story pretty dull
just collecting random things to unlock next chapter

About the Game
The legendary Knytt series continues with Nifflas’ latest creation; Knytt Underground™.

In this Knytteration; humans have long since abandoned the planet after practically destroying it in a war, five hundred years ago. The remaining population of Sprites, Fairies and various other life forms now live in mysterious tunnels underground — where they are trying to discover the secrets of their origin and the meaning of life.

Mixed up in all of this curiosity is Mi — a mute but extraordinary sprite! She develops special powers as the game progresses and embarks upon many exciting quests on her adventure. Her main goal is to find and ring the six bells of fate before time runs out. If she doesn’t a destructive chain reaction will begin that will obliterate the entire planet!

With an array of thrilling quests to complete, unique zen-like gameplay and plenty of dynamic characters to meet and guide you on your adventure — Knytt Underground™ delivers a captivating and unparalleled experience that will not disappoint! Explore over 1,800 rooms with the unique tried and tested mechanics that have already got over 1 million fans worldwide excited to run, jump, climb, swing and bounce with unparalleled freedom.